Question

A hammer is used to hit a nail into a block of wood. The hammer hits the nail with a speed of 8.0 m/s and then stops. The hammer is in contact with the nail for 0.0015 s.,hammer has mass 0.15 kg.Calculate the average force between the hammer and the nail.

Answer 1

800 Newtons

Explanation

The average force is the force exerted by a body moving at a defined rate of speed (velocity) for a defined period of time.

the average force is given by:

$F=ma$

and

$a=\frac{\Delta v}{\Delta t}$

$\begin{gathered} F_{average}=m\frac{\Delta v}{\Delta t} \\ where\text{ m is the mass of the objectt} \\ \Delta v\text{ is the change in velocity} \\ \Delta t=\text{ time} \end{gathered}$

Step 1

a) Let

$\begin{gathered} m=0.0015\text{ kg} \\ \Delta v=0.0015s \\ \Delta v=8\text{ }\frac{m}{s} \end{gathered}$

now, replace

$\begin{gathered} F=0.15\text{ kg}\frac{0-8\frac{m}{s}}{0.0015\text{ s}} \\ F=-800\text{ N} \end{gathered}$

the negative sign indicates the force is in the opposite way ( the force is exerted by the nail to the hammer), so the force is opposite to the direction of the movement

so, the answer is

800 Newtons

I hope this helps you